Adult acquired flatfoot

Last evidence check April 2011

Authors: Kerry Longrigg, Rebecca Hope, Jim Barrie


Patients with adult acquired flatfoot show several kinematic abnormalities which contribute an increased energy cost of walking. They have reduced hindfoot dorsiflexion and forefoot plantar flexion, and increased heel valgus and forefoot abduction. Orthotic treatment aims to reduce these abnormalities so as to improve symptoms and allow recovery of the soft tissue restraints and posterior tibial tendon.

In-shoe devices are probably most commonly used. The UCBL device cups the hindfoot closely. In a cadaver model Imhauser (2002) showed it to correct arch height, hindfoot valgus and 1st metatarsal position better than any other device. Less data is available on alternative in-shoe devices. Over-the-counter standard orthoses will be satisfactory for some patients. However, some require devices which are made from a mould or customised to their feet. In-shoe devices only work well in low-heeled lace-up footwear and it is important to explain this to the patient; a few patients will reject orthotic treatment not because the insoles do not work but because they do not accept the footwear requirements.

Flexible flatfeet (up to Truro stage 2b) can be treated with a UCBL-type device. This provides as much correction of hindfoot valgus and ankle loading as a calcaneal osteotomy (Havenhill 2005), and produces demonstrable improvement in gait parameters. Patients with fixed forefoot supination (Truro stages 2c-4) need an extension of the orthosis to "raise the ground" to the first ray. Patients in stage 3, with stiff deformities, need accommodative rather than corrective orthoses. However, orthotic treatment is still often successful.

Braces which extend above the ankle theoretically give additional support, although the evidence that they do so in real practice is limited. The Marzano brace combines a UCBL insole with a rear-entry supramalleolar component and achieves many of the same objectives. Imhauser (2002) found the Arizona brace was the most effective above-ankle devce in a cadaver model, controlling the arch and navicular height well. Lin (2008) reported 32 patients with stage 2 AAFF treated in a double-iron brace; 70% became brace-free, 15% continued with brace treatment and 15% underwent surgery. Weber used a moulded "shell" brace in 18 patients with stage 2 disease and followed them for a mean of over 5y; 15 improved in brace and had a final mean AOFAS score of 83/100, while 3 progressed to stiff deformities (stage 3) witha final AOFAS score of 69/100. Other recent braces include air bladders which can be adjusted to customise corrective pressures; again, the evidence for their effectiveness is limited.

In stiff deformities, more supportive and shock-absorbing devices will be more comfortable. Patients who have additional ankle deformities may benefit from a supramalleolar brace or solid ankle-foot orthosis. No clinical results have been reported specifically in these less common groups of patients.

Both Wapner and Chao (1999) and Jari et al (2002) found that 70% of patients were satisfactorily treated with orthoses and shoe modifications. Only about 10% were operated on, although a number of patients with significant continuing symptoms decided against surgery. Jackson (2009) re-reported Jari's series with longer follow-up and larger numbers. 80% of patients were successfully managed non-surgically, though some had decided to accept significant residual symptoms rather than have reconstructive surgery. Other patients had discarded their orthoses after a year or two without ill-effects. Nielsen (2011) reported 64 patients who had various non-surgical treatment modalities; only 8 (12.5%) progressed to surgery.

Recent studies (Alvarez 2006, Kulig 2009) have emphasised the use of orthotics as part of a multi-modal treatment programme supporting physiotherapy to improve muscle strength and protect against future injury.


Two important series have reported benefit from specific physiotherapy regimes, clarifying the role of rehabilitation. Alvarez (2006) found strength deficits in all leg muscle groups, most marked in the invertors at about 50% of normal strength. Patients underwent a strengthening programme lasting 1-2 months and in addition wore an above-ankle brace, whcih was converted to an in-shoe orthosis when pain subsided. 38/47 patients became comfortable and orthotic-free, four continued to wear in-shoe orthotics and five were operated on. 39/47 could perform a painless single foot heel raise. However, the average length of symptoms before treatment began was only 3 months and minimum follow-up was 1 year.

Other studies suggest muscle weakness is not the whole story. Kohl (2010) found no change in foot kinematics with tibialis posterior fatigue in healthy active subjects. Neville (2010) found that almost half of their patients with flatfoot deformity had normal posterior compartment strength when compared both with their asymptomatic side and with normal controls. Some patients also had weakness on the asymptomatic side.

Kulig (2009) reported a RCT comparing in-shoe orthotics alone with orthotics + concentric exercises and with orthotics +eccentric exercises. Although there were improvements in pain and Foot Function index (FFI) in all three groups, the largest improvement in FFI was in the eccentric exercise group. However, only 36 patients completed this study (12 in each group) and follow-up appears to have been only to the end of the 12-week treatment period.


Non-surgical treatment should be tried in every patient unless there are cogent reasons not to do so. Even imminent skin breakdown over the prominent talar head has been successfully treated with a Scotchcast diabetic boot followed by the use of a total contact inshoe orthosis.

Because the initial treatment is conservative in almost every case, patients whose referral letters imply that they have adult acquired flatfoot are primarily seen, in Blackburn, by the podiatrist rather than the surgical clinic.